Lyman, .457" diameter, 500 grain bullet mold, single cavity, steel blocks only. These precision mold blocks are made in the U.S.A. and tend to cost a bit more than other brands. They are nice quality. Special steel alloy mold blocks hold heat, for even casting temperature. Steel blocks almost never wear out, if properly stored. Blocks are made in one size, cut with a single cavity for large bullets. Mold handles are sold separately. Use large Lyman handles on all current production molds.